So I'm starting a business with my friend, and we started building our website. I found some really cool elements on other sites, the problem is... we can't figure out how to do these kinds of things. The only HTML/CSS/Javascript/JQuery training we've had is from w3schools.com so we don't understand a lot of things.

We'd liked the same type of navigation as found at the top of this website (naturally with different images and text).

And the same general layout of this website (with different images and colors).

We would really like to be able to accomplish these feats with nothing more advanced then JQuery, but if we must learn, then we must.

The first page's navigation is just a JQuery slider. I'm note sure I understand the layout question. Dreamweaver is not a graphics editing tool, it's for web programming. You will need Photoshop, Fireworks, Illustrator, Paint Shop Pro, etc, etc, type of a program to create graphics and then slice them up for use in Dreamweaver.

We would really like to be able to accomplish these feats with nothing more advanced then JQuery

The fact you ask this generalization after the first two questions is disconcerting. HTML and CSS give you the basics of web design. Then you go to client-slide languages like Javascript and server-side languages like PHP/ASP/.NET. If your project is not web-based there is no shame in hiring a designer to do it for you so that you can focus on the core of your bsuiness. However, if it is, I suggest learning HTML/CSS and not worrying about JQuery. Start with the basics and go from there.